1. Field of the Invention
Exemplary embodiments of the present invention relate to a system, apparatus and method for repairing a damaged and/or defective metal bump in a semiconductor device stack.
2. Description of the Conventional Art
Semiconductor devices employed in various electronic devices may be driven by, for example, demands for increased functionality, increased capacity, and/or smaller form factor. Three-dimensional stack technology may satisfy these demands. A three-dimensional device stack may include individual chips and/or packages which may be stacked in layers and may use, for example, a metal bump bonding technique.
Metal bumps may be electrical connections within the device stack and/or between the stack and a board. The metal bumps may require, for example, a flux coating layer which may reduce oxidation of the surface. The flux layer on the metal bumps may be often damaged and/or defective by heat and/or pressure during fabrication of the device stack. An oxide layer on the metal bumps, which may result in one or more damaged and/or defective electrical connections. The metal bumps may also be damaged and/or defective by, for example, thermal-induced stress.
Damaged and/or defective metal bumps may be repaired and/or changed. In a conventional method heat may be applied to the stack such that the individual chips and/or packages may be separated from each other. Damaged and/or defective bumps may be repaired and/or changed, and a new device stack may be created. This conventional method may create problems such as device failure which may result from heat applied to the device, and/or the existence of non-removed residue of the damaged and/or defective bump. The wafer level chip stack packages may be simultaneously fabricated at the wafer level and a particular chip stack package may be difficult to repair after stacking.
A conventional device stack which may include damaged and/or defective bumps may be rejected without being repaired and/or changed. This may result in a lower yield and/or a higher cost of fabrication of final products.